Invasion History

First Non-native North American Tidal Record: 1973
First Non-native West Coast Tidal Record: 1973
First Non-native East/Gulf Coast Tidal Record:

General Invasion History:

Myzobdella lugubris is a leech native to fresh waters of the eastern North America from the Great Lakes and Lake Winnipeg south to the Gulf Coast, and to estuaries and coastal waters from the Bay of Fundy to Texas (Daniels and Sawyer et al. 1975; Harris and Vogelbein 2006; U.S, National Museum of Natural History Collections 2017). It was formerly known as two species, Illinobdella moorei, a parasite of freshwater fishes, and M. lugubris, found on decapod crustaceans, but these names have been found to be synonymous. In Virginia, South Carolina and Mississippi estuaries, the leech lays its egg capsules on Blue Crabs (Callinectes sapidus), but as an adult, it parasitizes the White Catfsh (Amieurus catus) (Daniels and Sawyer et al. 1975). It is known from mysids, shrimps, crabs, especially Blue Crabs, and at least 26 species of freshwater and marine fishes (Sawyer et al. 1975).  A report from a Lionfish (Pterois sp.) off Florida (Ruiz-Carus et al. 2006) was a misidentification of a native leech (Trachelobdella lubrica) (Bullard et al. 2011).

 This leech has been widely introduced with game fishes from Eastern North America. In western North America, it is known from Colorado River basin (Amin et al. 1996) and the middle Columbia River (Becker and Dauble 1875), and from the tidal San Joaquin River (Hensley and Nahas 1975). This leech has also been collected from Puerto Rico (Williams et al. 1994), the Panama Canal, (US Museum of National History 2017) and Hawaii (Font 2003). The first Eastern Hemisphere record was tow specimens found on a European Pond Turtle in Italy (Liuzzo et al. 2018).

North American Invasion History:

Invasion History on the West Coast:

Myzobdella lugubris has been introduced to western North American reservoirs (Amin et al. 1996), the Columbia River (Becker and Dauble 1979), from Clear Lake, in the Sacramento River watershed (US National Museum of Natural History 2019), and the San Francisco Bay Delta, where it was collected from Ameiurus catus (White Catifsh) under the synonym Illinoia moorei (Hensley and Nahhas 1975), and from Largemouth Bass (Micropterus salmoides) (Troxel 2010).

Invasion History in Hawaii:

Myzobdella lugubris was found in fishes in 40% of freshwater streams on the Hawaiian islands. Likely vectors include aquarium and game fishes. It was found on 3 species of native gobies (Awaous guamensis; Eleotris sandwicensis; Sicyopterus stimpsoni), and 3 species of established live-bearing aquarium fishes: Poecilia mexicana (Mexican Molly); Poecilia reticulata (Guppy); Xiphophorus helleri (Swordtail) (Font 2003).

Invasion History Elsewhere in the World:

In 2016, two specimens of Myzobdella lugubris were collected on a European Pond Turtle ((Emys orbicularis hellenica) in a brackish canal in the Riserva Naturale dello Stato Oasi WWF 'LeCesine' in Apulia, Italy, near the mouth of Adriatic Sea. This is the first record of this leech in the Eastern Hemisphere, and the first record on a reptile (Liuzzo et al. 2018).


Myzobdella lugubris is a leech of fresh waters, and brackish-to-marine coastal waters. It has an elongate, slightly flattened club-like body. It has a smooth, translucent skin, lacking papillae, ocelli, or gills. The body consists of a head, an anterior region (tracheolosome, 6 segments) and a posterior urosome (12 segments), especially in adult or engorged individuals. The oral sucker is small, slightly wider than neck region and about three-fifths as wide as their terminal caudal sucker. It has one pair of eyespots, on the oral sucker. It reaches a length of 26 mm. It is an ectoparasite on many fishes and crustaceans (Sawyer et al.1975; Williams 2007).


Taxonomic Tree

Kingdom:   Animalia
Phylum:   Annelida
Class:   Clitellata
Subclass:   Hirudinea
Infraclass:   Euhirudinea
Order:   Rhynchobdellida
Family:   Piscicolidae
SubFamily:   Platybdellinae
Genus:   Myzobdella
Species:   lugubris


Ichthyobdella funduli (Verrill, 1872)
Illinobdella alba (Meyer, 1940)
Illinobdella elongata (Meyer, 1940)
Illinobdella moorei (Meyer, 1940)
Illinobdella richardsoni (Meyer, 1940)
Myzobdella funduli (Verrill, 1872)
Piscicola punctata (Moore, 1912)

Potentially Misidentified Species

Trachelobdella lubrica

Myzobdella lubrica was initially reported from Lionfish (Pterois sp. collected off North Carolina (Ruiz-Carus et al. 2006). However, a re-examination of the voucher specimens and later collections found that the leeches on lionfishes were Trachobdella lubrica, a frequent parasite of scorpeanid fishes (Bullard et al. 2011).



Myzobdella lugubris tolerates a wide range of temperature and salinity, at least 3–28 °C, and 0 to 26 PSU (Sawyer et al. 1975), and possibly higher. This leech is known to parasitize mysids (Neomysis americana, Blue Crabs (Callinectes sapidus), shrimps (Palaemonetes spp.; Penaeus spp.), more than 40 species of freshwater and marine fishes, and one occurrence on a turtle (Sawyer et al. 1975; Font 2003; Harris and Vogelbine 2006; Liuzzo et al. 2018). Usually only one or two leeches attach to a Palaemonetes, ~5 to Blue Crabs, and 9.5 from a group of White Catfish (Ameiurus catus), although one White Catfish had 500 leeches (Sawyer et al. 1975). In Back Bay, Virginia, Largemouth Bass (Micropterus salmoides) had 1–15 leeches mostly in the oral region. However, infested fish did not differ from un-parasitzed fishes in plasma glucose, cortisol, or general condition (Pomposini et al. 2018).


Blood of fishes and decapod crustaceans

Trophic Status:




General HabitatFresh (nontidal) MarshNone
General HabitatGrass BedNone
General HabitatCoarse Woody DebrisNone
General HabitatSwampNone
General HabitatNontidal FreshwaterNone
General HabitatTidal Fresh MarshNone
General HabitatSalt-brackish marshNone
Salinity RangeLimnetic0-0.5 PSU
Salinity RangeOligohaline0.5-5 PSU
Salinity RangeMesohaline5-18 PSU
Tidal RangeSubtidalNone
Vertical HabitatEpibenthicNone
Vertical HabitatNektonicNone

Life History

Myzobdella lugubris is a leech known from freshwater, brackish, and marine habitats, and a wide variety of freshwater, estuarine, and marine fish hosts, from a number of estuarine decapod crustacean hosts, and in one case, a turtle (Sawyer et al. 1975; Font 2003; Liuzzo et al. 2018). Leeches are hermaphroditic, and eggs are laid in cocoons, often on the shells of crabs (e.g., Callinectes sapidus) or shrimps (e.g., Palaemonetes). Coccoons hatch in about 11 days at 25 °C (Sawyer et al. 1975), or at 28–48 days at 17–22 °C. Cocoons contain a single egg (Saglam et al. 2018). Given its native and introduced ranges M. lugubris seems to be very flexible in its hosts.

Tolerances and Life History Parameters

Minimum Temperature (ºC)2.8Field (Sawyer et al. 1975)
Maximum Temperature (ºC)28Field (Sawyer et al. 1975)
Minimum Salinity (‰)0Field (Sawyer et al. 2019)
Maximum Salinity (‰)26Field. In experiments, 15 PSU with direct transfer (Sawyer et al. 2019). Records in full seawater suggest genetic diversity or a species complex.
Broad Temperature RangeNoneCold Temperate-Tropical
Broad Salinity RangeNoneNontidal Limnetic-Mesohaline

General Impacts

Leeches are ectoparasites, sucking blood and body fluids from their hosts. Although Myzobdella lugubris is aesthically repulsive to fishermen, there is little evidence of negative impacts on crustacean or fish populations (Daniels and Sawyer 1975; Sawyer et al. 1975; Pomposini et al. 2019).

Regional Distribution Map

Bioregion Region Name Year Invasion Status Population Status
S080 Charleston Harbor 0 Native Estab
G170 West Mississippi Sound 0 Native Estab
GL-II Lake Erie 0 Native Estab
CAR-VII Cape Hatteras to Mid-East Florida 0 Native Estab
S180 St. Johns River 0 Native Estab
CAR-I Northern Yucatan, Gulf of Mexico, Florida Straits, to Middle Eastern Florida 0 Native Estab
S010 Albemarle Sound 0 Native Estab
NA-ET3 Cape Cod to Cape Hatteras 0 Native Estab
SP-XXI None 0 Def Estab
N195 _CDA_N195 (Cape Cod) 0 Native Estab
M080 New Jersey Inland Bays 0 Native Estab
M130 Chesapeake Bay 0 Native Estab
S030 Bogue Sound 0 Native Estab
S130 Ossabaw Sound 0 Native Estab
G120 Choctawhatchee Bay 0 Native Estab
G150 Mobile Bay 0 Native Estab
G230 Mermentau River 0 Native Estab
CAR-IV None 1968 Def Estab
G260 Galveston Bay 0 Native Estab
P090 San Francisco Bay 1973 Def Estab
SEP-H None 1974 Def Estab
LWINNI Lake Winnipeg 0 Native Estab
NA-ET2 Bay of Fundy to Cape Cod 0 Native Estab
PAN_PAC Panama Pacific Coast 1974 Def Estab
MED-VII None 2016 Def Unk
S010 Albemarle Sound 0 Native Estab
M090 Delaware Bay 1851 Native Estab

Occurrence Map

OCC_ID Author Year Date Locality Status Latitude Longitude


Amin, Omar M.; Minckley, Wendell L. (1996) Parasites of some fish introduced into an Arizona reservoir, with notes on introductions., Journal of the Helminthological Society of Washington 63(2): 193-200

Bullard, S. A.; Barse, A. M.; Curran, S. S.; Morris, J. A., Jr. (2011) First record of a digenean from invasive lionfish, Pterois cf. volitans, (Scorpaeniformes: Scorpaenidae) in the northwestern Atlantic Ocean, Journal of Parasitology 97(5): 833-837

Daniels, Bruce A.; Sawyer, Roy T. (1975) The biology of the leech Myzobdella lugubris infesting blue crabs and catfish., Biological Bulletin 148: 193-198

Font, William F. (2003) The global spread of parasites: what do Hawaiian streams tell us?, BioScience 53(11): 1061-1067

Hensley, Gary H., Nahhas, F.M. (1975) Parasites of fishes from the Sacramento-San Joaquin Delta, California., California Fish and Game 61(4): 201-208

Liuzzo, M.; Alfonso, G.; Beli, E.; Arculeo, M.; Marrone, F. (2018) First record of the alien leech Myzobdella lugubris Leidy, 1851 (Hirudinea, Piscicolidae) in the Palearctic, Limnetica 37(2): 311-318
DOI: 10.23818/limn.37.25

Noga, Edward J.; BuIIis,’Robert A.; Miller, Grover C. (1990) Epidemic Oral Ulceration in Largemouth Bass (Micropterus salmoides) Associated with the Leech Myzobdella lugubris, Journal of Wildlife Diseases 26(1): 132-154
DOI: 10.7589/0090-3558-26.1.132

Ruiz-Carus, Ramon; Matheson, Richard E.; Roberts, Daniel E.; Whitfield, Paula E. (2006) The western Pacific red lionfish, Pterois volitans (Scorpaenidae), in Florida: evidence for reproduction and parasitism in the first exotic marine fish established in state waters., Biological Conservation 128: 384-390

Saglam, Naim; Saunders, Ralph; Lang, Shirley A.' Shain, Daniel H. (2018) Phylogeny and cocoon production in the parasitic leech Myzobdella lugubris Leidy, 1851 (Hirudinidae, Piscicolidae), Acta Parasitologica 63(1): 15-26
DOI: 10.1515/ap-2018-0002

Sawyer, Roy T.; Lawler, Adirian L.; Overstreet, robin M. (1975) Marine leeches of the eastern United States and the Gulf of Mexico with a key to the species., Journal of Natural History 9: 633-667

Troxel, Daniel J. (2010) Parasites of Largemouth Bass (Micropterus salmoides) in northern California , Humboldt State University, Arcata, California. Pp. <missing location>

U.S. National Museum of Natural History 2002-2021 Invertebrate Zoology Collections Database.

Williams, Julianne I. (2007) Monograph of the North American freshwater fish leeches (Oligochaeta: Hirudinida ; Piscicolidae) and molecular phylogeny of the family Piscicolidae, College of William and Mary - Virginia Institute of Marine Science, Gloucester Point, Virginia. Pp. <missing location>